The power supply apparatus includes a switching element connected to a primary winding of a transformer to which an input voltage is applied; a feedback unit configured to output a first feedback voltage according to an output voltage, the output voltage induced in a secondary winding of the transformer and output to a load; a current detection unit for detecting a current flowing to the switching element and output a second feedback voltage according to the current detected; a limiting unit for limiting the first feedback voltage so that the current flowing to the switching element is below a predetermined current value; an output unit for outputting a driving signal for the switching element based on the first feedback voltage limited by the limiting unit and on the second feedback voltage; and a control unit for controlling the switching element according to the driving signal output from the output unit.
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1. A power supply apparatus comprising: a rectification unit configured to rectify an AC voltage from an AC power supply to generate an input voltage; a transformer having a primary winding and a secondary winding; a first switching element connected to the primary winding of the transformer to which the input voltage is applied; a feedback unit configured to output a first feedback voltage according to an output voltage, the output voltage being induced in the secondary winding of the transformer and output to a load; a current detection unit configured to detect a current flowing to the first switching element and output a second feedback voltage according to the current detected; an output unit configured to output a driving signal for the first switching element based on the first feedback voltage and on the second feedback voltage; a control unit configured to control an operation of the first switching element according to the driving signal output from the output unit; and a limiting unit configured to, in a case where the output voltage is a first voltage, supply the first feedback voltage to the output unit, and in a case where the output voltage is a second voltage less than the first voltage, limit the first feedback voltage so as not to exceed a predetermined voltage and supply the limited first feedback voltage to the output unit.
This invention relates to power supply apparatuses and addresses the problem of controlling output voltage stability, particularly under varying load conditions. The apparatus includes a rectification unit that converts AC voltage from a power supply into a DC input voltage. A transformer with primary and secondary windings is used to step down or up this voltage. A primary switching element, connected to the transformer's primary winding, is controlled to regulate power transfer. A feedback unit monitors the output voltage across a load and generates a first feedback voltage proportional to it. A current detection unit monitors the current flowing through the primary switching element and generates a second feedback voltage. An output unit combines these two feedback voltages to create a driving signal for the primary switching element. A control unit uses this driving signal to operate the switching element. A key feature is a limiting unit. When the output voltage is at a normal level (a first voltage), the first feedback voltage is passed directly to the output unit. However, if the output voltage drops to a lower level (a second voltage), the limiting unit restricts the first feedback voltage to a predetermined maximum value before it is sent to the output unit. This prevents excessive control signals and potential damage to the switching element or other components during low output voltage conditions.
2. The power supply apparatus according to claim 1 , wherein the limiting unit has a second switching element configured to be turned on or off according to a state of the load, and a first voltage limiting element connected in series with the second switching element and configured to limit the first feedback voltage to prevent the first feedback voltage output from the feedback unit from exceeding the predetermined voltage in a case where a current of the predetermined current value flows to the second switching element, and wherein the first voltage limiting element is configured to, is a case where the second switching element is in a turn-on state, correct the first feedback voltage to prevent the current flowing to the second switching element from exceeding the predetermined current value.
A power supply apparatus includes a feedback unit that generates a first feedback voltage based on an output voltage of the power supply. The apparatus also has a limiting unit that regulates this feedback voltage to prevent it from exceeding a predetermined voltage level. The limiting unit contains a second switching element that operates based on the load state and a first voltage limiting element connected in series with the second switching element. When a current reaches a predetermined value through the second switching element, the first voltage limiting element restricts the first feedback voltage to ensure it does not surpass the predetermined voltage. Additionally, if the second switching element is in an on state, the first voltage limiting element adjusts the first feedback voltage to prevent the current through the second switching element from exceeding the predetermined value. This design ensures stable power delivery by dynamically controlling feedback voltage and current levels in response to load conditions. The apparatus is particularly useful in power supply systems where precise voltage regulation and current protection are required to maintain safe and efficient operation.
3. The power supply apparatus according to claim 2 , wherein the limiting unit further includes another second switching element or other second switching elements and another first voltage limiting element or other first voltage limiting elements connected in series with the second switching elements, wherein each of the second switching elements are turned on or off according to a different state of the load, and wherein each of the first voltage limiting clement limiting elements limit the first feedback voltage to below a different voltage value.
This invention relates to a power supply apparatus designed to regulate output voltage by dynamically adjusting feedback voltage based on load conditions. The apparatus includes a limiting unit that controls the feedback voltage to prevent excessive voltage fluctuations during load changes. The limiting unit contains multiple second switching elements and corresponding first voltage limiting elements connected in series. Each second switching element is activated or deactivated based on different load states, allowing the apparatus to adapt to varying load conditions. The first voltage limiting elements ensure the feedback voltage remains below distinct voltage thresholds, providing precise control over the output voltage. By incorporating multiple switching and limiting elements, the apparatus achieves stable power delivery across a range of operational scenarios, improving efficiency and reliability in power supply systems. The dynamic adjustment mechanism ensures that the feedback voltage is appropriately limited to maintain system stability, particularly during transient load changes. This design enhances the robustness of the power supply apparatus in applications requiring precise voltage regulation under varying load demands.
4. The power supply apparatus according to claim 2 , wherein the second switching element is turned on in a case where the load is in a light-load state in which the output voltage is the second voltage, and turned off in a case where the load is in a heavy-load state in which the output voltage is the first voltage.
A power supply apparatus is designed to efficiently manage power delivery to a load under varying conditions. The apparatus includes a switching regulator that adjusts its output voltage between a first voltage for heavy-load states and a second voltage for light-load states. A second switching element is incorporated to optimize power efficiency. When the load is in a light-load state, the second switching element is activated, allowing the output voltage to be maintained at the second voltage, which is lower than the first voltage. This reduces power consumption and improves efficiency. Conversely, when the load transitions to a heavy-load state, the second switching element is deactivated, enabling the output voltage to switch to the first voltage to meet higher power demands. The apparatus ensures stable power delivery while minimizing energy waste, particularly during light-load operation. The switching element's state is dynamically controlled based on the load condition, enhancing overall system efficiency. This design is particularly useful in applications where power consumption varies significantly, such as in portable electronics or energy-efficient systems.
5. The power supply apparatus according to claim 2 , wherein the second switching element is turned on upon power-on of the power supply apparatus.
A power supply apparatus includes a first switching element and a second switching element connected to a power source. The first switching element is configured to control the flow of power from the power source to a load, while the second switching element is designed to manage power distribution within the apparatus itself. Upon power-on of the apparatus, the second switching element is automatically turned on to initiate power flow to internal components, ensuring proper initialization and operation. This design allows for controlled power distribution, reducing startup surges and improving system stability. The apparatus may also include additional circuitry to regulate voltage or current levels, ensuring safe and efficient power delivery to connected devices. The second switching element's activation at startup ensures that essential internal circuits receive power before external loads are engaged, preventing potential damage or malfunctions. This configuration is particularly useful in applications requiring reliable power management, such as industrial equipment, consumer electronics, or renewable energy systems. The apparatus may further incorporate feedback mechanisms to monitor and adjust power delivery dynamically, enhancing overall performance and safety.
6. The power supply apparatus according to claim 2 , wherein the output unit has a second voltage limiting element configured to correct the first feedback voltage for limiting a value of the current flowing to the second switching elements, and wherein the value of the current flowing to the second switching element corresponding to the first feedback voltage and limited by the second voltage limiting element is larger than the predetermined current value.
A power supply apparatus includes a control circuit that regulates output voltage by adjusting switching elements in response to a feedback voltage. The apparatus addresses the problem of maintaining stable current delivery while preventing excessive current flow that could damage components. The control circuit generates a first feedback voltage based on the output voltage and uses this to control first switching elements that regulate power delivery. A second set of switching elements is also present, and their current flow is managed to ensure safe operation. To achieve this, an output unit includes a second voltage limiting element that modifies the first feedback voltage to limit current through the second switching elements. The current allowed through these elements, as determined by the modified feedback voltage, is set to be higher than a predetermined safe current threshold. This ensures that the second switching elements can handle higher loads without triggering protective shutdowns, while still preventing dangerous overcurrent conditions. The apparatus thus balances efficient power delivery with component protection.
7. The power supply apparatus according to claim 1 , comprising a voltage detection unit having resistors and configured to output a third feedback voltage resulting from dividing the input voltage by the resistors, wherein the output unit has an inverting amplifier to which a reference voltage output from a reference power supply and the third feedback voltage output from the voltage detection unit are input, wherein the inverting amplifier outputs an inverted voltage resulting from amplifying and inverting a polarity of the third feedback voltage with reference to the reference voltage, and the output unit outputs a driving signal for the first switching element based on the inverted voltage output from the inverting amplifier, the first feedback voltage, and the second feedback voltage.
This invention relates to a power supply apparatus designed to regulate output voltage by controlling a switching element. The apparatus addresses the challenge of maintaining stable output voltage in response to varying input conditions, such as fluctuations in input voltage or load demand. The power supply includes a voltage detection unit that divides the input voltage using resistors to generate a third feedback voltage proportional to the input voltage. This third feedback voltage is fed into an inverting amplifier within the output unit, where it is compared against a reference voltage from a reference power supply. The inverting amplifier amplifies and inverts the third feedback voltage relative to the reference voltage, producing an inverted voltage. The output unit then generates a driving signal for the first switching element based on this inverted voltage, along with first and second feedback voltages derived from other components in the system. The driving signal adjusts the switching element to regulate the output voltage, ensuring stability and efficiency in power delivery. The apparatus leverages feedback control to dynamically compensate for input variations, improving performance in applications requiring precise voltage regulation.
8. The power supply apparatus according to claim 7 , wherein the higher the input voltage is, the lower the inverted voltage output from the inverting amplifier is, and the lower the input voltage is, the higher the inverted voltage output from the inverting amplifier is.
This invention relates to a power supply apparatus with an inverting amplifier that dynamically adjusts its output voltage based on the input voltage. The apparatus addresses the challenge of maintaining stable power delivery in systems where input voltage fluctuations can occur, such as in renewable energy systems or battery-powered devices. The inverting amplifier converts the input voltage into an inverted output voltage, where the relationship between the input and output is inversely proportional. Specifically, as the input voltage increases, the inverted output voltage decreases, and vice versa. This ensures that the output voltage compensates for input variations, providing a more consistent power supply to connected loads. The apparatus may include additional components, such as a voltage divider or feedback loop, to regulate the inversion process and enhance stability. The dynamic adjustment mechanism helps prevent overvoltage or undervoltage conditions, improving system reliability and efficiency. This design is particularly useful in applications requiring precise voltage regulation under varying input conditions.
9. The power supply apparatus according to claim 7 , wherein the reference voltage of the reference power supply is set according to a limited current value for the current flowing to the first switching element.
A power supply apparatus includes a reference power supply that generates a reference voltage, which is used to control the operation of a first switching element. The reference voltage is set based on a limited current value for the current flowing through the first switching element. This ensures that the current through the switching element does not exceed a predefined threshold, preventing damage to the component. The apparatus may also include a control circuit that adjusts the reference voltage dynamically to maintain stable operation under varying load conditions. The first switching element is part of a switching regulator or converter, which converts an input voltage to a desired output voltage. The reference power supply provides a stable reference for comparison with feedback signals to regulate the output voltage or current. By setting the reference voltage according to the limited current value, the apparatus ensures safe and efficient power delivery while protecting the switching element from overcurrent conditions. This design is particularly useful in applications requiring precise current control, such as in power management systems for electronic devices.
10. The power supply apparatus according to claim 7 , wherein the output unit has a second voltage limiting element configured to correct the first feedback voltage for limiting a value of the current flowing to the first switching element, and wherein the value of the current flowing to the first switching element corresponding to the first feedback voltage and limited by the second voltage limiting element is larger than the value of the current flowing to the first switching element and limited by the inverted voltage.
A power supply apparatus includes a switching regulator with a first switching element and a control circuit that generates a first feedback voltage based on an output voltage. The apparatus further includes an output unit that provides power to a load. The output unit has a second voltage limiting element that corrects the first feedback voltage to limit the current flowing to the first switching element. The current value allowed by the second voltage limiting element is greater than the current value limited by an inverted voltage, ensuring stable operation under varying load conditions. The control circuit may also include a first voltage limiting element that limits the first feedback voltage to prevent excessive current through the first switching element. The apparatus ensures efficient power conversion while protecting the switching element from overcurrent conditions. The second voltage limiting element dynamically adjusts the current limit based on the first feedback voltage, improving transient response and reliability. The design is particularly useful in applications requiring precise current control and protection in switching power supplies.
11. The power supply apparatus according to claim 1 , comprising a smoothing unit configured to smooth the input voltage generated by the rectification unit.
A power supply apparatus includes a rectification unit that converts an alternating current (AC) input voltage into a direct current (DC) voltage. The apparatus further includes a smoothing unit that smooths the DC voltage generated by the rectification unit to reduce voltage fluctuations and provide a stable output. The smoothing unit may use capacitors, inductors, or other passive components to filter out high-frequency noise and ripple from the rectified voltage. This ensures a cleaner and more consistent DC output, which is essential for powering sensitive electronic devices. The apparatus may also include additional components such as a voltage regulation unit to maintain the output voltage within a desired range, even under varying load conditions. The overall design aims to improve power quality, efficiency, and reliability in electronic systems.
12. An image forming apparatus comprising: an image forming unit configured to form an image on a recording material; and a power supply apparatus configured to generate power for forming the image, wherein the power supply apparatus comprises: a rectification unit configured to rectify an AC voltage from an AC power supply to generate an input voltage; a transformer having a primary winding and a secondary winding; a first switching element connected to the primary winding of the transformer to which the input voltage is applied; a feedback unit configured to output a first feedback voltage according to an output voltage, the output voltage being induced in the secondary winding of the transformer and output to a load; a current detection unit configured to detect a current flowing to the first switching element and output a second feedback voltage according to the current detected; an output unit configured to output a driving signal for the first switching element based on the first feedback voltage and on the second feedback voltage; a control unit configured to control an operation of the first switching element according to the driving signal output from the output unit; and a limiting unit configured to, in a case where the output voltage is a first voltage, supply the first feedback voltage to the output unit, and in a case where the output voltage is a second voltage less than the first voltage, limit the first feedback voltage so as not to exceed a predetermined voltage and supply the limited first feedback voltage to the output unit.
This invention relates to an image forming apparatus, such as a printer or copier, that includes a power supply system designed to regulate and stabilize the output voltage supplied to the image forming unit. The apparatus addresses the problem of maintaining consistent power delivery to the image forming unit, particularly during fluctuations in load conditions or input voltage variations, which can affect print quality and device reliability. The power supply apparatus converts an AC voltage from an external source into a stable DC output voltage using a rectification unit, a transformer with primary and secondary windings, and a switching element connected to the primary winding. A feedback unit monitors the output voltage induced in the secondary winding and generates a first feedback voltage proportional to this output. A current detection unit measures the current flowing through the switching element and produces a second feedback voltage based on this current. An output unit generates a driving signal for the switching element using both feedback voltages, while a control unit regulates the switching element's operation according to this signal. A limiting unit ensures voltage stability by adjusting the first feedback voltage. When the output voltage is at a normal operating level (first voltage), the feedback voltage is supplied directly. If the output voltage drops below a threshold (second voltage), the limiting unit restricts the feedback voltage to prevent excessive current draw, maintaining safe and stable operation. This design improves power supply reliability and protects the apparatus from voltage surges or drops.
13. The image forming apparatus according to claim 12 , comprising a controller configured to control the image forming unit, wherein the controller turns off the first switching element in a heavy-load state in which the output voltage is the first voltage and image forming is performed, and turns on the first switching element in a light-load state in which the output voltage is the second voltage and image forming is not performed.
This invention relates to an image forming apparatus designed to optimize power consumption by dynamically adjusting electrical components based on operational states. The apparatus includes an image forming unit that generates images and a power supply circuit that provides electrical power. The power supply circuit has a first switching element connected to a transformer, which steps up or down an input voltage to produce an output voltage. The apparatus operates in two distinct states: a heavy-load state and a light-load state. In the heavy-load state, the image forming unit is actively producing images, and the output voltage is set to a first, higher voltage level. During this state, the first switching element is turned off to ensure stable power delivery. In the light-load state, the image forming unit is idle, and the output voltage is reduced to a second, lower voltage level. In this state, the first switching element is turned on to minimize power consumption. A controller manages these transitions, ensuring efficient power usage by activating or deactivating the switching element based on the operational state of the apparatus. This design reduces energy waste during idle periods while maintaining performance during active image formation.
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December 26, 2018
January 14, 2020
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